The γ-phase was bombarded with 15keV He+ ions, to a dose of 8.6 x 1020/m2 (4.4dpa), in a high-voltage transmission electron microscope at room temperature. Defect clusters became visible, using high-voltage transmission electron microscopy, after a dose of 4.7 x 1019/m2 (0.24dpa). They were mainly planar defects, and had the character of domain structures with their edges parallel to the (111) planes of the matrix. They were several nm in size. Bubbles of He with irregular shapes were observed after a dose of 5.7 x 1020/m2 (2.9dpa). Post-bombardment annealing (673K, 0.5h) enhanced the growth of the domain structure. An analysis of the high-voltage transmission electron microscopic images, and selected-area diffraction patterns, indicated the formation of rotated domains which had the same structure as the matrix but were rotated by 90º with respect to the matrix.

High-Resolution Electron Microscopy of γ-TiAl Irradiated with 15keV Helium Ions at Room Temperature. M.Song, K.Furuya, T.Tanabe, T.Noda: Journal of Nuclear Materials, 1999, 271-272, 200-4